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US4936922A - High-purity cleaning system, method, and apparatus - Google Patents

High-purity cleaning system, method, and apparatus Download PDF

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US4936922A
US4936922A US07355699 US35569989A US4936922A US 4936922 A US4936922 A US 4936922A US 07355699 US07355699 US 07355699 US 35569989 A US35569989 A US 35569989A US 4936922 A US4936922 A US 4936922A
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solvent
chamber
cleaning
system
pressure
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Expired - Fee Related
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US07355699
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Roger L. Cherry
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Roger L. Cherry
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B08CLEANING
    • B08BCLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
    • B08B15/00Preventing escape of dirt or fumes from the area where they are produced; Collecting or removing dirt or fumes from that area
    • B08B15/02Preventing escape of dirt or fumes from the area where they are produced; Collecting or removing dirt or fumes from that area using chambers or hoods covering the area
    • B08B15/026Boxes for removal of dirt, e.g. for cleaning brakes, glove- boxes
    • B05B14/49
    • B05B15/80
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B08CLEANING
    • B08BCLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
    • B08B3/00Cleaning by methods involving the use or presence of liquid or steam
    • B08B3/006Cabinets or cupboards specially adapted for cleaning articles by hand
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24HEATING; RANGES; VENTILATING
    • F24FAIR-CONDITIONING, AIR-HUMIDIFICATION, VENTILATION, USE OF AIR CURRENTS FOR SCREENING
    • F24F3/00Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems
    • F24F3/12Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling
    • F24F3/16Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling by purification, e.g. by filtering; by sterilisation; by ozonisation
    • F24F3/1603Air-conditioning systems in which conditioned primary air is supplied from one or more central stations to distributing units in the rooms or spaces where it may receive secondary treatment; Apparatus specially designed for such systems characterised by the treatment of the air otherwise than by heating and cooling by purification, e.g. by filtering; by sterilisation; by ozonisation by filtering
    • F24F3/1607Clean air work stations, i.e. selected areas within a space to which filtered air is passed
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H01L21/00Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/67Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
    • H01L21/67005Apparatus not specifically provided for elsewhere
    • H01L21/67011Apparatus for manufacture or treatment
    • H01L21/67017Apparatus for fluid treatment
    • H01L21/67028Apparatus for fluid treatment for cleaning followed by drying, rinsing, stripping, blasting or the like
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/10Greenhouse gas [GHG] capture, material saving, heat recovery or other energy efficient measures, e.g. motor control, characterised by manufacturing processes
    • Y02P70/36Recycling or reuse of a liquid sprayed or atomised

Abstract

A system for high purity cleaning of components includes a cleaning chamber which is maintained at a pressure above ambient atmospheric pressure. A gas-glide transporter extends through the cleaning chamber and includes a pair of slightly tilted elongate tubes having a plurality of tiny holes therein. The tubes communicate with a source of filtered pressurized nitrogen. A tray for carrying components to be cleaned is adapted to fit on the tubes and slide down the transporter on a frictionless cushion of nitrogen. Components are cleaned of very small particles by using a high pressure spray of individual droplets of solvent which knock the particles off the component to be cleaned. The particles, solvent and solvent vapor are swept away from the component being cleaned by a stream of dry, filtered air. Two types of solvent systems are shown. One supplies liquid solvent under high pressure to the solvent sprayer while the other uses liquid solvent and a compressed gas under high pressure as a propellant to force the solvent through the small orifice of the sprayer. The cleaning chamber group includes a control panel which controls solvent supply and recovery modules. The cleaning chamber group is modular so that it may be placed in a Class 100 environment.

Description

This is a continuation-in-part of Application Ser. No. 07/053,202, filed May 21, 1987, now U.S. Pat. No. 4,832,753.

BACKGROUND OF THE INVENTION

This invention relates to a system, method, and apparatus for high-purity cleaning of manufacturing components, and particularly to such a system, method, and apparatus which enable components to be cleaned, dried, and packaged in a clean environment.

Certain industries, such as manufacturers of silicon chips or other semi-conductors, require that manufacturing and storage components be extremely clean, substantially free of contaminant films and micron and sub-micron particle contamination One method of high-purity cleaning is to wash the items to be cleaned with a high-pressure (2000-2400 psi) spray of solvent as described in Capella et al. U.S. Pat. No. 4,443,269. However, the process and apparatus disclosed in Capella are designed specifically for the removal of radioactive particles and contaminants and are not particularly suited to clean an item for future use so that the item becomes and remains substantially free of all contaminants and particles, not merely free of radioactive contaminants and particles.

For example, the method of Capella employs a cleaning chamber having sub-atmospheric pressure so that radioactive particles do not "blow" out of the chamber. This creates the possibility that non-radioactive particles proximate the cleaning chamber will be drawn into the chamber, especially when the chamber is opened to remove a component from the chamber. Since Capella is concerned primarily with radioactive particles, Capella's system filters particles out of the solvent and then reuses the filtered solvent, which could contain dissolved contaminants

The solvents typically used in systems of the type described above are from the chlorofluorocarbon group (CFC) such as freon, and are now considered undesirable because it is thought that such gases deplete the ozone layer. Accordingly, it would be preferable to use a solvent which does not have negative health or enviromental considerations. A solvent which could be safely vented directly to the atmosphere without the need for a solvent recovery system would also be highly desirable.

SUMMARY OF THE INVENTION

The present invention provides a system, method, and apparatus for high-purity cleaning of components and for maintaining the components in a clean condition during drying and packaging. The system according to the present invention is modular, so that the cleaning chamber and the system controls may be isolated within a class 100 clean environment, with the "dirty" components located remote from, or sealed off from, the cleaning chamber and controls

The cleaning chamber of the system includes an air delivery and filtration system that directs a stream of dry, warm, filtered air directly onto the items being cleaned while the item is simultaneously being sprayed with a high-pressure dispersion of solvent droplets. The air flow provided by the air system is sufficient, in volume and purity, to make the inside of the cleaning chamber a Class 10 environment. The air system maintains the pressure in the cleaning chamber above ambient atmospheric pressure.

The cleaning system also includes a solvent pumping and spraying system capable of delivering a spray of solvent at up to 6000 psi. The combination of high pressure and a small spraying orifice acts to create a spray of tiny solvent droplets which act as "fluid hammers" to knock very small, sub-micron particles off of the components to be cleaned, dispersing the particles into the chamber where they are carried away by the stream of clean, dry air flowing over the item and through the chamber.

An alternative system employs liquid CO2 as a solvent, avoiding the environmental and health-related drawbacks of other commonly used solvents. Liquid CO2 is supplied at one pressure and combined with a gaseous propellant under very high pressure to create the spray of tiny droplets.

The droplets which comprise the high pressure spray have a slight positive charge whereas ions associated with the contaminant particles typically have a slight negative charge Thus, the contaminant particles tend to adhere to the solvent after they have been knocked off the item to be cleaned.

For automated cleaning, the cleaning chamber includes a gas-glide transporter for moving the components to be cleaned into, through, and out of the cleaning chamber without substantially introducing extraneous particulate contamination into the chamber.

The cleaning chamber may be constructed to any size and may be adapted to cooperate with an adjacent drying chamber, which, like the cleaning chamber, may be operated at an environment down to Class 10.

Accordingly, it is a principal object of the present invention to provide an improved high-purity cleaning system, method, and apparatus.

It is a particular object to provide such a system, method, and apparatus which not only cleans the material of pre-existing contaminants, but prevents contamination during cleaning, drying, and packaging.

It is an associated object to provide a cleaning system having a positive pressure within the cleaning chamber.

It is a further object to provide a system which supplies the cleaning chamber with a flow of dry, warm, filtered air sufficient to maintain a Class 10 environment.

It is another object to provide a cleaning system to clean objects with a very high-pressure solvent spray of tiny droplets to knock particles off of the components to be cleaned.

It is a further object to provide a cleaning system which can transport material into, through, and out of the cleaning chamber substantially without the introduction of extraneous contaminants.

It is another object to provide a system having a cleaning chamber and a control system which can be operated within a clean environment with other components of the system remote or sealed off from the clean environment.

It is an additional object to provide a system and method employing an environmentally safe solvent.

It is a further object to provide a system and method which employ electrostatic principles to remove contaminant particles from the item to be cleaned and to prevent such particles from re-adhering to the item.

The foregoing and other objectives, features, and advantages of the invention will be more readily understood upon consideration of the following detailed description of the invention, taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of an exemplary system according to the present invention.

FIG. 2 is a schematic view of an exemplary cleaning chamber including air supply system, condensate system, and gas-glide transporter.

FIG. 3 is a schematic view of an exemplary system including a distillation group.

FIG. 4 is an artist's view of an exemplary cleaning chamber group including a control panel, a drying chamber, and a gas-glide transporter.

FIG. 5 is an elevational view of a cleaning tray mounted on a cross-section of the gas-glide transporter.

FIG. 6 is a partial top view of the gas-glide transporter shown in FIG. 5.

FIG. 7 is a block diagram of an alternative system according to the present invention.

FIG. 8 is a schematic view of the alternative system of FIG. 7.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1-6 show one exemplary embodiment of the cleaning system of the present invention, and features thereof.

Starting with FIG. 3, an exemplary cleaning system according to the present invention includes a cleaning chamber group 10, a control system 12, a used solvent recovery group 14, and a pump group 16. If the system is distilling and reusing the newly distilled solvent, a distillation group 18 is located between the used solvent recovery group and the pump group. If the system is using new solvent, the recovered solvent is fed to a used solvent container 20, and new solvent is supplied to the pump group from a new solvent container 22.

Turning to FIG. 1, an exemplary embodiment of a system which does not use a distillation group includes a cleaning chamber group 10, a used solvent recovery group 14, a pump group 16, new solvent container 22, and a used solvent container 20. The basic operation of the system may be explained by tracing the flow of solvent through the system

A positive displacement, high-pressure pump 24 draws new, clean solvent out of container 22, through filter 26 and pushes the new solvent through the solvent supply line 78 toward the location of the cleaning chamber group. The pump is an airless type pump which is adapted to supply a liquid, under pressure, without air entrained in the liquid. The pump is powered by a regulated supply of air pressure, such as "factory air" through the pump control air line 80. A regulator 82 ensures that air is supplied to the pump at a constant pressure. The pump control air line 80 includes an emergency shutdown valve 84 to shut down the pump if the control system 12 senses a dangerous situation.

The pump is "on demand," it does not operate unless pressure in the solvent supply line 78 falls below a predetermined level. The use of an on-demand pump is important for several reasons. An operating pump, with parts moving against other parts, has a tendency to shed particles. A pump which operates continuously also has a tendency to heat up, which increases particle shedding. An on-demand pump also eliminates the need for complex valving to relieve the pressure created by constant operation. A pump which has very few moving parts which are wetted, i.e. touched by the solvent, is well suited for this purpose.

The primary purpose of filter 26, preferably a 400 mesh filter which is capable of filtering particles as small as 1-2 microns, is to ensure that such particles do not enter into and score the inner working surfaces of the pump which operates with rather small tolerances A 0.2 micron vent filter 28 on the new solvent container ensures that particles are not drawn into the container when air enters the container through the vent. A load cell 30, detects the weight of the new solvent container and is operatively connected to the control system to alert the operator, or to shut down the system, when the container is nearly empty.

Following the flow of solvent downstream from the pump, a surge surpresser 86 dampens out surges caused by sudden operation of the pump. Prior to entering the cleaning chamber 32 the new solvent passes through another filter 88 adapted to filter out all particles larger than 0.2 microns. A pressure transducer 34, downstream of the filter, provides the operator with a readout of the pressure in the solvent supply line at the control panel and can cause the valve 84 in the pump 25 control air line 80 to close if the pressure in the solvent supply line becomes too high.

In the cleaning chamber, the solvent is fed to a solvent gun 36 through a flexible hose and is shot from the solvent gun in a very high-pressure spray of tiny droplets whose impact is sufficient to actually knock sub-micron particles off the surface of the component being cleaned The combination of a very high-pressure (2,500-6,000) and a relatively small orifice (less than twenty thousandths) on the solvent gun yield a solvent spray which is characterized by very small, fast-moving droplets traveling in excess of 100 meters per second at approximately 4"-18" from the orifice of the solvent gun. The droplets act as a "fluid hammer" to actually knock particles off the component to be cleaned. Closer to the orifice the spray has not yet had an opportunity to form a dispersion of droplets, while further than 18" from the orifice the solvent may partially vaporize, reducing its effectiveness at cleaning. The high pressure and small orifice result in a flow of 0.5-1.0 gallons per minute, a substantial savings over other systems which use much more solvent without cleaning as effectively.

Applicant believes that Capella, which discloses a system which delivers "solvent at a range of 4-4.6 gallons per minute at a pressure in the range of 2,000-2400 pounds per square inch," actually delivers multiple streams of liquid solvent onto the article to be cleaned. A stream of liquid solvent flowing over a surface does not have the same mechanical impact as a dispersion of individual droplets impacting the surface. When liquid flows over a surface, a thin, boundary layer of essentially zero velocity is created. Small submicron particles can "hide out" in this boundary layer or hide out in eddys in the solvent flow caused by small surface irregularities. Comparatively, individual droplets, from a source of the identical pressure, can create three to four times the impact on a small particle than can a stream of fluid.

In addition to the fluid hammer effect of the tiny droplets, applicant directs a strong flow of dry, filtered air over the item being cleaned and through the chamber. The air flow is introduced at the top of the chamber and drawn out through the bottom of the creating a strong, substantially laminar flow of air through the chamber. This air stream carries the solvent droplets, solvent vapor, and free particles away from the item being cleaned so that particles do not readhere to the wet surface. While free particles are carried away with the solvent vapor other particles are likely to become bound to the solvent droplets.

Applicant has found that creating the high pressure, high speed, dispersion of individual solvent droplets imparts a slight positive charge to the solvent droplets. Ions typically associated with contaminant particles give the particles a slight negative charge, while the item to be cleaned typically has a slight positive charge. When the contaminant particles are knocked off the item to be cleaned, the slight positive charge of the droplets tend to cause the negatively charged contaminant particles to adhere to the solvent droplets and/or solvent vapor and be swept away in the air stream rather than re-adhering to the item to be cleaned. Applicant believes that this beneficial electrostatic effect does not occur when a contaminated item is washed with a stream of solvent, even a relatively high pressure stream.

The air supply system of the present invention moves a sufficient volume of very clean, dry air through the cleaning chamber to meet the requirements for a Class 10 environment as described in Federal Standard 209(c) of the "Federal Standard Clean Room and Work Station Requirements, Controlled Environment." The clean, dry air, which is maintained near ambient temperature, flowing past the article being cleaned at approximately 50 feet per minute tends to dry the article very quickly thereby discouraging subsequent particle re-adhesion common to wetted surfaces.

As the spray of solvent droplets travels further away from the gun, some of the solvent may vaporize because the pressure in the chamber, which is slightly above atmospheric pressure, is much less than that of the pressurized solvent. The vaporized solvent as well as the other air in the chamber is drawn out of the bottom of the chamber and up through a condensor 38 including cooling coils 40 which cool the vapor/air mixture from the chamber so that the solvent condenses and drains out of the chamber through a drain 42. Liquid solvent in the chamber would also be directed toward the drain by the V-shaped bottom 44 of the chamber. The used solvent is collected in a recovery tank 46 including a pump 48 and a float switch 50 which automatically pumps the used solvent to the used solvent container 20.

After the solvent has condensed out of the chamber atmosphere, the remaining air is drawn up past heating coils 52 which raise the temperature of the air to compensate for the cooling effect of the condensor. The heating coils are controlled by a thermo-couple 100 to raise the temperature of the air up to or above ambient temperature. The air is then drawn through a pre-filter 92 and a fan 94, and pushed through a high efficiency particle air ("HEPA") filter 54 to remove any free particle contaminants in the air. The HEPA used by applicant can remove 99.99% at 0.3 microns. The dissolved contaminants and particulate contaminants which become bound to the solvent were carried away with the condensed solvent.

In order to maintain the pressure within the cleaning chamber above atmospheric pressure, a make-up air damper 96 is controlled by a pressure transducer 98 to add sufficient air to keep the pressure in the chamber above atmospheric pressure. The air supply system exchanges the air in the cleaning chamber approximately every 10 seconds.

Turning to FIG. 4, an exemplary cleaning chamber 32 is shown. A control panel 12 is co-located with the cleaning chamber. The control panel is connected to the various valves, sensors, and controls discussed above so that the operator can monitor and control the entire system from his position at the cleaning chamber. The operator can reach into the cleaning chamber to operate the solvent gun and manipulate the components to be cleaned through a pair of gloves 102 which are sealed in a see-through wall of the chamber. A drying chamber 58 is arranged next to the cleaning chamber and, like the cleaning chamber, is also sealed. In the exemplary embodiment shown in FIG. 4, the air system would provide the same flow of clean, dry air to the drying chamber as has been described with respect to the cleaning chamber. A door 62 between the cleaning and drying chambers may be opened by the operator to move articles from the cleaning chamber to the drying chamber. Similar doors 62 on the entrance to cleaning chamber and the exit from drying chamber permit articles to be moved into and out of the chambers. A gas-glide transporter 60 extends through the cleaning and drying chambers.

With attention to FIGS. 1, 2, 5, and 6, as well as FIG. 4, the gas-glide transporter includes a pair of rectangular tubes 64 and 64'. As shown in FIG. 6, the top of tube 64 includes many small holes 66 5 in a biased pattern while the top and both sides of the guide tube 64' also include such holes in a similar pattern. Except for these small holes, the tubes are otherwise airtight and are fed with a pressurized filtered gas such as nitrogen (N2) as shown in FIG. 1. A bottle of N2 68 under pressure, controlled by a valve 70 and passing through a 0.2 micron filter 88, is fed into the cleaning chamber and into the gas-glide tubes 64 and 64' as shown in FIG. 2.

As shown in FIG. 4, a cleaning tray 72 is adapted to be supportably guided by the tubes. The cleaning tray includes one supporting foot 74 which fits over the top and sides of the guide tube 64' and a supporting sole 76 which is positioned over the top of the other tube 64. The tubes are slightly slanted so that the infeed end of the tubes near the cleaning chamber is slightly higher than the outfeed end near the drying chamber. When pressurized nitrogen is fed to the tubes, the tray is supported by a frictionless cushion of N2 between the foot and sole of the tray and their respective tubes. Since the tubes are slanted, the tray will glide down the tube toward the lower end. When the supply of N2 is cut off, the tray settles directly onto the tubes and the friction between the tray and the tubes prevents the tray from moving. In this fashion movement of the tray into, through, and out of the chambers may be completely and precisely controlled by the operator through the control system from his position at the cleaning chamber.

Typical transport systems such as belts or chains, which are powered by motors, and supported by bearings or journals, tend to be "dirty" in that they have many moving parts which can generate and shed particles. The gas-glide disclosed above has no moving parts and is not apt to introduce any particles or other contaminants into the chamber since the N2 is filtered prior to entering the chambers.

As previously noted, doors 62 at either end of the chamber may be opened by the operator to permit the components to be placed or transported into or out of the chambers. Several techniques eliminate or reduce the introduction of particles into the chambers when the chambers are opened. First, the modular design of the system enables the "dirty" functions of the system to be located remote from the cleaning chamber and control system so that the cleaning chamber itself may be placed in a clean environment, up to class 100. Pumps, motors and other components of the system which would not be able to operate in a class 100 environment are enclosed or separated from the cleaning chamber group. Placing the cleaning chamber in such a clean environment reduces the possibility of contamination when the chamber is opened. In addition, the chamber of the present invention is maintained at a pressure which is above atmospheric pressure, causing air to flow out of the chambers when the chamber doors are opened.

The system and method have been described above in operation with a solvent such as Freon. Other solvents such as denatured alcohol, carbon tetracloride, or dionized water, or combinations of solvents, would behave somewhat differently. For example, when alcohol is used as a solvent, there would be less vaporization than Freon, and when deionized water is used there would be virtually no vaporization. However, operation of the system would be essentially the same, with more of the solvent running out of the chamber as a liquid and less being condensed out of the chamber atmosphere.

FIGS. 7 and 8 show an alternative embodiment of the cleaning system of the present invention. In many respects the alternative system shown in FIGS. 7 and 8 is very similar to that described above with respect to FIGS. 1-6. Like the first system, the alternative system cleans by creating a high pressure spray consisting primarily of individual droplets of solvent traveling at a high rate of speed to knock contaminant particles off the item to be cleaned. Simultaneously, with this "fluid hammer" spray, a laminar flow of warm, dry, filtered air is passed over the item to be cleaned carrying away solvent vapor and contaminant particles which have been knocked off the item. As with the previously described system, the chamber is capable of being substantially sealed from the atmosphere and a slight positive pressure is maintained in the chamber to ensure that contaminants are not drawn into the chamber.

The major difference in the alternative system is that rather than supplying the solvent sprayer with a solvent under high pressure (above 2500 psi), the system supplies the sprayer with liquid solvent at a first pressure and also with a gas propellant at a second, higher, pressure. Another major difference between the systems is that the alternative system uses a liquid solvent such as CO2 which is environmentally safe and can be vented directly to the atmosphere.

Starting with FIG. 7, a block diagram of the alternative system includes a cleaning chamber group 210, a control system 212, a solvent recovery group 214, a solvent supply 222, and a compressed gas supply 221. If the solvent is not to be recovered, and can be safely vented to the atmosphere, an exhaust vent 223 is shown.

Turning to FIG. 8, the cleaning chamber group 210 includes the chamber itself 232 and a solvent sprayer 236 for dispersing a high pressure spray of solvent droplets. Pure liquid CO2 is supplied to the sprayer through a solvent supply line 278 from a container 222 of compressed liquid CO2. Liquid CO2 at approximately 300 psi is readily available. If necessary, the liquid CO2 may be filtered to achieve the requisite purity. A solenoid valve 225 in the solvent supply line controls the supply of liquid CO2 to the solvent sprayer 236.

The solvent supply line is heat wrapped with electrical heating tape 227 to maintain the liquid CO2 at ambient temperatures, preferably above 60° F. A disruption in the substantially laminar flow of the CO2 within the solvent supply line could allow air bubbles which may be inside the supply line to combine with the CO2 and and allow some liquid CO2 to enter a gaseous phase. This change of phase removes heat (heat of vaporization) from the surrounding liquid CO2 which could cause the liquid CO2 to freeze into dry ice and clog the solvent supply line. Accordingly, it is important to keep the liquid CO2 at a sufficiently high temperature so that such freezing and clogging does not occur. A heat control 229 enables the heating of the solvent supply line to be adjusted as required.

The solvent sprayer is also supplied with a supply of filtered gas, such as air, under high pressure (3000 psi). The air is supplied through air supply line 237 by a compressor 233 such as an "on demand" pure oxygen compressor, which is controlled by a suitable control device 235.

The compressed air at 3000 psi and liquid CO2 at 300 psi are combined in the solvent sprayer immediately adjacent a small (less than 0.002") orifice so that the solvent is forced through the orifice under high pressure so as to form a spray of individual solvent droplets. The flow rate of the liquid CO2 is less than 0.3 gallons per minute. It may also be possible to combine the liquid CO2 and compressed air in a mixing chamber prior to exiting the orifice. Appropriate valving and venturis within the solvent sprayer prevent the 3000 psi compressed air from backing up the 300 psi liquid CO2 line.

The remainder of the cleaning chamber group is essentially as described above with respect to the embodiment depicted in FIGS. 1-6. After exiting the chamber 232, the air is drawn up past heating coils 252 controlled by thermo-couple 300, through a pre-filter 292, and a fan 294 into the chamber. A make-up air damper 296 is controlled by a pressure transducer 298. Most of the liquid CO2 vaporizes in the cleaning chamber. As the air and CO2 vapor leave the chamber through the V-shaped bottom 244, the heavier CO2 vapor is drawn out through the drain 242 by the exhaust fan at vent 223. Any liquid solvent will drain into a solvent recovery container 214.

The gas glide transporter described above with respect to FIGS. 1-6 is compatable with the alternative embodiment shown in FIGS. 7 and 8.

Although the alternative embodiment has been described employing compressed air and liquid CO2, other compressed gases are also suitable and other solvents may also be suitable if they have similar characteristics to CO2 and Freon TF such as viscosity, temperature range, and ability to remove non-volatile residue, mainly hydrocarbons.

The terms and expressions which have been employed in the foregoing specification are used therein as terms of description and not of limitation, and there is no intention, in the use of such terms and expressions, of excluding equivalents of the features shown and described or portions thereof, it being recognized that the scope of the invention is defined and limited only by the claims which follow.

Claims (6)

What is claimed is:
1. A method of high purity cleaning including particle removal from an item to be cleaned, comprising:
(a) placing an item to be cleaned in a chamber which is capable of providing a clean environment;
(b) providing a high pressure solvent sprayer for directing and dispersing a spray consisting of individual droplets of solvent upon said item to be cleaned;
(c) striking said item to be cleaned with said droplets of solvent dispersed from said sprayer so as to dislodge contaminant particles from said item; and
(d) providing said sprayer with a supply of liquid solvent at a first pressure above ambient pressure and a supply of gaseous propellant at a second pressure above said first pressure, said second pressure being above 2500 psi.
2. The method of claim 1 wherein said liquid solvent includes CO2.
3. The method of claim 2, including the step of providing heating means for maintaining the temperature of said supply of liquid CO2 above ambient temperature.
4. The method of claim 1, including the step of forcing said solvent through an orifice at said second pressure, said orifice having a diameter of less than 0.002 inch.
5. The method of claim 1, including the step of forcing said solvent through an orifice at said second pressure wherein said solvent and said propellent are combined immediately prior to passing through said orifice.
6. The method of claim 1 wherein said item to be cleaned has a slight positive charge, ions associated with said particles have a slight negative charge and said individual droplets have a slight negative charge so that said particles adhere to said solvent after being dislodged from said item to be cleaned.
US07355699 1987-05-21 1989-05-23 High-purity cleaning system, method, and apparatus Expired - Fee Related US4936922A (en)

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Cited By (35)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4122699A1 (en) * 1991-04-19 1993-01-21 Edwards Kniese & Co Hochvakuum Workplace for the treatment of contaminated parts
US5209028A (en) * 1992-04-15 1993-05-11 Air Products And Chemicals, Inc. Apparatus to clean solid surfaces using a cryogenic aerosol
US5273060A (en) * 1992-06-26 1993-12-28 Martin Marietta Corporation Alcohol spray cleaning system
US5302324A (en) * 1990-03-20 1994-04-12 Morikawa Sangyo Kabushiki Kaisha Method for decontaminating substances contaminated with radioactivity, and method for decontaminating the materials used for said decontamination
US5315793A (en) * 1991-10-01 1994-05-31 Hughes Aircraft Company System for precision cleaning by jet spray
US5339844A (en) * 1992-08-10 1994-08-23 Hughes Aircraft Company Low cost equipment for cleaning using liquefiable gases
DE4310267A1 (en) * 1993-03-30 1994-10-06 Schreiber Walter Dipl Ing Fh Device for cleaning articles
US5355901A (en) * 1992-10-27 1994-10-18 Autoclave Engineers, Ltd. Apparatus for supercritical cleaning
US5364474A (en) * 1993-07-23 1994-11-15 Williford Jr John F Method for removing particulate matter
EP0631846A1 (en) * 1993-06-14 1995-01-04 International Business Machines Corporation Mounting apparatus for cryogenic aerosol cleaning
US5409418A (en) * 1992-09-28 1995-04-25 Hughes Aircraft Company Electrostatic discharge control during jet spray
US5417768A (en) * 1993-12-14 1995-05-23 Autoclave Engineers, Inc. Method of cleaning workpiece with solvent and then with liquid carbon dioxide
US5467492A (en) * 1994-04-29 1995-11-21 Hughes Aircraft Company Dry-cleaning of garments using liquid carbon dioxide under agitation as cleaning medium
US5549512A (en) * 1994-11-30 1996-08-27 Lucent Technologies Inc. Minienvironment for hazardous process tools
US5603892A (en) * 1994-06-09 1997-02-18 Fujitsu Limited System for maintaining a controlled atmosphere in an electronic circuit package
US5651723A (en) * 1994-04-13 1997-07-29 Viratec Thin Films, Inc. Method and apparatus for cleaning substrates in preparation for deposition of thin film coatings
US5810942A (en) * 1996-09-11 1998-09-22 Fsi International, Inc. Aerodynamic aerosol chamber
US5881577A (en) * 1996-09-09 1999-03-16 Air Liquide America Corporation Pressure-swing absorption based cleaning methods and systems
US5904737A (en) * 1997-11-26 1999-05-18 Mve, Inc. Carbon dioxide dry cleaning system
US5931721A (en) * 1994-11-07 1999-08-03 Sumitomo Heavy Industries, Ltd. Aerosol surface processing
US5942037A (en) * 1996-12-23 1999-08-24 Fsi International, Inc. Rotatable and translatable spray nozzle
US5961732A (en) * 1997-06-11 1999-10-05 Fsi International, Inc Treating substrates by producing and controlling a cryogenic aerosol
US5967156A (en) * 1994-11-07 1999-10-19 Krytek Corporation Processing a surface
US6036786A (en) * 1997-06-11 2000-03-14 Fsi International Inc. Eliminating stiction with the use of cryogenic aerosol
US6039059A (en) * 1996-09-30 2000-03-21 Verteq, Inc. Wafer cleaning system
US6216302B1 (en) * 1997-11-26 2001-04-17 Mve, Inc. Carbon dioxide dry cleaning system
US6397421B1 (en) * 1999-09-24 2002-06-04 Micell Technologies Methods and apparatus for conserving vapor and collecting liquid carbon dioxide for carbon dioxide dry cleaning
US6442980B2 (en) * 1997-11-26 2002-09-03 Chart Inc. Carbon dioxide dry cleaning system
US6572457B2 (en) 1998-09-09 2003-06-03 Applied Surface Technologies System and method for controlling humidity in a cryogenic aerosol spray cleaning system
US6589592B1 (en) 1999-09-24 2003-07-08 Micell Technologies Methods of coating articles using a densified coating system
US6656017B2 (en) 2001-04-24 2003-12-02 David P. Jackson Method and apparatus for creating an open cell micro-environment for treating a substrate with an impingement spray
US20060118138A1 (en) * 2003-06-02 2006-06-08 Spiegelman Jeffrey J Method for the removal of airborne molecular contaminants using oxygen and/or water gas mixtures
US20090272461A1 (en) * 2005-08-03 2009-11-05 Alvarez Jr Daniel Transfer container
US8273185B2 (en) 2009-07-25 2012-09-25 Ceramex Limited Cleaning a vehicle exhaust filter
EP3195943A1 (en) * 2016-01-20 2017-07-26 Yongkang Xieheng Zhejiang Province Industry & Commerce Co., Ltd Anti-splash cleaning machine

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4443269A (en) * 1979-10-01 1984-04-17 Health Physics Systems, Inc. Tool decontamination method
US4606774A (en) * 1984-07-30 1986-08-19 The Dow Chemical Company Process for removing contaminants from soils
US4832753A (en) * 1987-05-21 1989-05-23 Tempress Measurement & Control Corporation High-purity cleaning system, method, and apparatus

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4443269A (en) * 1979-10-01 1984-04-17 Health Physics Systems, Inc. Tool decontamination method
US4606774A (en) * 1984-07-30 1986-08-19 The Dow Chemical Company Process for removing contaminants from soils
US4832753A (en) * 1987-05-21 1989-05-23 Tempress Measurement & Control Corporation High-purity cleaning system, method, and apparatus

Cited By (64)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5302324A (en) * 1990-03-20 1994-04-12 Morikawa Sangyo Kabushiki Kaisha Method for decontaminating substances contaminated with radioactivity, and method for decontaminating the materials used for said decontamination
DE4122699A1 (en) * 1991-04-19 1993-01-21 Edwards Kniese & Co Hochvakuum Workplace for the treatment of contaminated parts
US5315793A (en) * 1991-10-01 1994-05-31 Hughes Aircraft Company System for precision cleaning by jet spray
US5209028A (en) * 1992-04-15 1993-05-11 Air Products And Chemicals, Inc. Apparatus to clean solid surfaces using a cryogenic aerosol
US5273060A (en) * 1992-06-26 1993-12-28 Martin Marietta Corporation Alcohol spray cleaning system
US5339844A (en) * 1992-08-10 1994-08-23 Hughes Aircraft Company Low cost equipment for cleaning using liquefiable gases
US5409418A (en) * 1992-09-28 1995-04-25 Hughes Aircraft Company Electrostatic discharge control during jet spray
US5526834A (en) * 1992-10-27 1996-06-18 Snap-Tite, Inc. Apparatus for supercritical cleaning
US5355901A (en) * 1992-10-27 1994-10-18 Autoclave Engineers, Ltd. Apparatus for supercritical cleaning
DE4310267A1 (en) * 1993-03-30 1994-10-06 Schreiber Walter Dipl Ing Fh Device for cleaning articles
EP0712690A1 (en) * 1993-06-14 1996-05-22 International Business Machines Corporation Mounting apparatus for cryogenic aerosol cleaning
EP0631846A1 (en) * 1993-06-14 1995-01-04 International Business Machines Corporation Mounting apparatus for cryogenic aerosol cleaning
US5486132A (en) * 1993-06-14 1996-01-23 International Business Machines Corporation Mounting apparatus for cryogenic aerosol cleaning
US5558110A (en) * 1993-07-23 1996-09-24 Williford, Jr.; John F. Apparatus for removing particulate matter
US5364474A (en) * 1993-07-23 1994-11-15 Williford Jr John F Method for removing particulate matter
EP0641611A1 (en) * 1993-09-07 1995-03-08 Hughes Aircraft Company Low cost equipment for cleaning using liquefiable gases
US5417768A (en) * 1993-12-14 1995-05-23 Autoclave Engineers, Inc. Method of cleaning workpiece with solvent and then with liquid carbon dioxide
US5651723A (en) * 1994-04-13 1997-07-29 Viratec Thin Films, Inc. Method and apparatus for cleaning substrates in preparation for deposition of thin film coatings
US5467492A (en) * 1994-04-29 1995-11-21 Hughes Aircraft Company Dry-cleaning of garments using liquid carbon dioxide under agitation as cleaning medium
US5603892A (en) * 1994-06-09 1997-02-18 Fujitsu Limited System for maintaining a controlled atmosphere in an electronic circuit package
US5967156A (en) * 1994-11-07 1999-10-19 Krytek Corporation Processing a surface
US6203406B1 (en) 1994-11-07 2001-03-20 Sumitomo Heavy Industries, Ltd. Aerosol surface processing
US5931721A (en) * 1994-11-07 1999-08-03 Sumitomo Heavy Industries, Ltd. Aerosol surface processing
US5549512A (en) * 1994-11-30 1996-08-27 Lucent Technologies Inc. Minienvironment for hazardous process tools
US5881577A (en) * 1996-09-09 1999-03-16 Air Liquide America Corporation Pressure-swing absorption based cleaning methods and systems
US5810942A (en) * 1996-09-11 1998-09-22 Fsi International, Inc. Aerodynamic aerosol chamber
US7211932B2 (en) 1996-09-30 2007-05-01 Akrion Technologies, Inc. Apparatus for megasonic processing of an article
US6681782B2 (en) 1996-09-30 2004-01-27 Verteq, Inc. Wafer cleaning
US20060180186A1 (en) * 1996-09-30 2006-08-17 Bran Mario E Transducer assembly for megasonic processing of an article
US6039059A (en) * 1996-09-30 2000-03-21 Verteq, Inc. Wafer cleaning system
US6140744A (en) * 1996-09-30 2000-10-31 Verteq, Inc. Wafer cleaning system
US6684891B2 (en) 1996-09-30 2004-02-03 Verteq, Inc. Wafer cleaning
US20040206371A1 (en) * 1996-09-30 2004-10-21 Bran Mario E. Wafer cleaning
US6295999B1 (en) 1996-09-30 2001-10-02 Verteq, Inc. Wafer cleaning method
US8771427B2 (en) 1996-09-30 2014-07-08 Akrion Systems, Llc Method of manufacturing integrated circuit devices
US7117876B2 (en) 1996-09-30 2006-10-10 Akrion Technologies, Inc. Method of cleaning a side of a thin flat substrate by applying sonic energy to the opposite side of the substrate
US6463938B2 (en) 1996-09-30 2002-10-15 Verteq, Inc. Wafer cleaning method
US8257505B2 (en) 1996-09-30 2012-09-04 Akrion Systems, Llc Method for megasonic processing of an article
US7268469B2 (en) 1996-09-30 2007-09-11 Akrion Technologies, Inc. Transducer assembly for megasonic processing of an article and apparatus utilizing the same
US20060175935A1 (en) * 1996-09-30 2006-08-10 Bran Mario E Transducer assembly for megasonic processing of an article
US5942037A (en) * 1996-12-23 1999-08-24 Fsi International, Inc. Rotatable and translatable spray nozzle
US6036786A (en) * 1997-06-11 2000-03-14 Fsi International Inc. Eliminating stiction with the use of cryogenic aerosol
US5961732A (en) * 1997-06-11 1999-10-05 Fsi International, Inc Treating substrates by producing and controlling a cryogenic aerosol
US6442980B2 (en) * 1997-11-26 2002-09-03 Chart Inc. Carbon dioxide dry cleaning system
US5904737A (en) * 1997-11-26 1999-05-18 Mve, Inc. Carbon dioxide dry cleaning system
US6216302B1 (en) * 1997-11-26 2001-04-17 Mve, Inc. Carbon dioxide dry cleaning system
US6572457B2 (en) 1998-09-09 2003-06-03 Applied Surface Technologies System and method for controlling humidity in a cryogenic aerosol spray cleaning system
US20030182731A1 (en) * 1999-09-24 2003-10-02 Worm Steve Lee Cleaning apparatus having multiple wash tanks for carbon dioxide dry cleaning and methods of using same
US6397421B1 (en) * 1999-09-24 2002-06-04 Micell Technologies Methods and apparatus for conserving vapor and collecting liquid carbon dioxide for carbon dioxide dry cleaning
US6921420B2 (en) 1999-09-24 2005-07-26 Micell Technologies Apparatus and methods for conserving vapor in a carbon dioxide dry cleaning system
US20040083555A1 (en) * 1999-09-24 2004-05-06 Brainard David E. Apparatus for conserving vapor in a carbon dioxide dry cleaning system
US6666050B2 (en) 1999-09-24 2003-12-23 Micell Technologies, Inc. Apparatus for conserving vapor in a carbon dioxide dry cleaning system
US7114508B2 (en) 1999-09-24 2006-10-03 Micell Technologies Cleaning apparatus having multiple wash tanks for carbon dioxide dry cleaning and methods of using same
US6589592B1 (en) 1999-09-24 2003-07-08 Micell Technologies Methods of coating articles using a densified coating system
US20070017557A1 (en) * 1999-09-24 2007-01-25 Micell Technologies Cleaning apparatus having multiple wash tanks for carbon dioxide dry cleaning and methods of using same
US6795991B2 (en) 1999-09-24 2004-09-28 Micell Technologies Apparatus for conserving vapor in a carbon dioxide dry cleaning system
US20040255393A1 (en) * 1999-09-24 2004-12-23 Brainard David E. Apparatus and methods for conserving vapor in a carbon dioxide dry cleaning system
US6656017B2 (en) 2001-04-24 2003-12-02 David P. Jackson Method and apparatus for creating an open cell micro-environment for treating a substrate with an impingement spray
US20070137676A1 (en) * 2003-06-02 2007-06-21 Spiegelman Jeffrey J Method for the removal of airborne molecular contaminants using extra clean dry air
US8075704B2 (en) 2003-06-02 2011-12-13 Entegris, Inc. Method for the removal of airborne molecular contaminants using oxygen and/or water gas mixtures
US20060118138A1 (en) * 2003-06-02 2006-06-08 Spiegelman Jeffrey J Method for the removal of airborne molecular contaminants using oxygen and/or water gas mixtures
US20090272461A1 (en) * 2005-08-03 2009-11-05 Alvarez Jr Daniel Transfer container
US8273185B2 (en) 2009-07-25 2012-09-25 Ceramex Limited Cleaning a vehicle exhaust filter
EP3195943A1 (en) * 2016-01-20 2017-07-26 Yongkang Xieheng Zhejiang Province Industry & Commerce Co., Ltd Anti-splash cleaning machine

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